Rashi on Deuteronomy 15:10/רש"י על דברים ט״ו:י׳

1נתן תתן לו THOU SHALT SURELY GIVE HIM — even hundred times (Sifrei Devarim 117:6).

2לו implies between him and you (privately) (Sifrei Devarim 117:7.)

3כי בגלל הדבר הזה BECAUSE THAT FOR THIS THING [THE LORD THY GOD SHALL BLESS THEE] — (the word is taken in its literal sense of “word”, for it would have sufficed to state כי בגלל זה suggesting): even if you only say (intend) to give but are later unable to do so you will receive a reward for the mere saying (intention) together with the reward for the action (Sifrei Devarim 117:8).